package com.jk.vehicle.core.filter;

import com.jk.vehicle.core.web.XssHttpServletRequestWrapper;
import org.apache.commons.lang3.BooleanUtils;
import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * XSS过滤器
 *
 * @author KangJian
 * @date 2018/07/19
 */
public class XssFilter implements Filter {

	/**
	 * 日志
	 */
	private static Logger logger = LoggerFactory.getLogger(XssFilter.class);

	/**
	 * 是否过滤富文本内容
	 */
	private static boolean IS_INCLUDE_RICH_TEXT = false;

	/**
	 * 排除列表
	 */
	private List<String> excludes = new ArrayList<String>();

	@Override
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain)
			throws IOException, ServletException {
		if (logger.isDebugEnabled()) {
			logger.debug("xss filter is open");
		}

		HttpServletRequest req = (HttpServletRequest) request;
		HttpServletResponse resp = (HttpServletResponse) response;
		if (handleExcludeURL(req, resp)) {
			filterChain.doFilter(request, response);
			return;
		}

		XssHttpServletRequestWrapper xssRequest = new XssHttpServletRequestWrapper((HttpServletRequest) request,
				IS_INCLUDE_RICH_TEXT);
		filterChain.doFilter(xssRequest, response);
	}

	/**
	 * 处理请求
	 * @param request
	 * @param response
	 * @return
	 */
	private boolean handleExcludeURL(HttpServletRequest request, HttpServletResponse response) {

		if (excludes == null || excludes.isEmpty()) {
			return false;
		}

		String url = request.getServletPath();
		for (String pattern : excludes) {
			Pattern p = Pattern.compile("^" + pattern);
			Matcher m = p.matcher(url);
			if (m.find()) {
				return true;
			}
		}

		return false;
	}

	@Override
	public void init(FilterConfig filterConfig) throws ServletException {
		logger.info("Init XssFilter");
		String isIncludeRichText = filterConfig.getInitParameter("isIncludeRichText");
		if (StringUtils.isNotBlank(isIncludeRichText)) {
			IS_INCLUDE_RICH_TEXT = BooleanUtils.toBoolean(isIncludeRichText);
		}

		String temp = filterConfig.getInitParameter("excludes");
		if (temp != null) {
			String[] url = temp.split(",");
			for (int i = 0; url != null && i < url.length; i++) {
				excludes.add(url[i]);
			}
		}
	}

	@Override
	public void destroy() {
		logger.info("Destroy XssFilter");
	}

}
